A switch for high voltage responsible for interrupting a fault current has to satisfy the following two items when interrupting the current.
One is to surely extinguish, in a very short time, an arc generated between contacts after the opening. The other is to prevent dielectric breakdown when a transient recovery voltage rapidly rises between the contacts after the arc extinction.
In recent years, there has been widely adopted a puffer switch of a type in which one circuit breaker part having connectable/separable contacts are housed in a pressure vessel in which SF6 gas as insulating gas is sealed, and the insulating gas is sprayed to the contacts at the time of an interrupting operation, to extinguish an arc. In this type, the aforesaid two items have to be achieved with a single circuit breaker.
On the other hand, there has also been developed a switch of a type that achieves the interruption of the fault current by connecting circuit breaker parts each specialized in satisfying one of the aforesaid two items. That is, this is a switch of a type having the plural circuit breaker parts and assigning the roles separately to the respective circuit breaker parts. Such a switch is formed by separating an inner space of a pressure vessel, housing the circuit breaker part excellent in arc extinction performance and the circuit breaker part excellent in insulation performance in the one and other parts of the space respectively, and electrically connecting the both in series.
In the switch in which the circuit breaker parts specialized in the aforesaid interrupting duties respectively are coupled, each of the circuit breaker parts has its own connectable/separable contacts, and an interrupting operation and a conducting operation of all the contacts are performed by a single operation part (actuator), so that a load to the operation part is great.
A cause of a great load to the operation part is not only an increase of the number of the contacts which perform the interrupting/conducting operations but also a loss due to structures for transmitting a driving force of the single operation part to the plural contacts. Since the operation part is provided on an outer side of a pressure vessel in which the contacts are disposed, the number of transmitting parts including a rotating lever and a link mechanism also increases in order to transmit the driving force to the contacts in the tank. Accordingly, a weight of the structures for transmitting the driving force of the operation part to the contacts also increases.
Therefore, a large driving force is necessary, and the kind and size of the operation part are limited. When operation energy cannot be made large, there is a disadvantage that the interruption time becomes long.
A gas switch according to this embodiment has an object to provide a switch which is capable of easily achieving interruption duties required for a high-voltage switch and whose interruption time is short.